Opener BlackFly

Discussion in 'Hangar Flying' started by markaeric, Jul 16, 2018.

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  1. Aug 3, 2018 #461

    davidb

    davidb

    davidb

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    I’d like to hear more details of flying the simulator. I can’t find any details with a google search. Seems there should be some YouTube videos since they were letting people fly it. Can anyone find even a picture or did they not allow photography?
     
  2. Aug 3, 2018 #462

    pictsidhe

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    If I had a toy quadcopter, I'd be tempted to strap a pair of hotwired XPS wings to it and see what happens.
     
  3. Aug 3, 2018 #463

    Topaz

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    >snork< Thanks.

    More seriously, I let this get under my skin and took it too far. Sorry, guys. I should've heeded my own counsel and just stated my opinion and moved on. It just is a pet peeve of mine to watch "what everyone knows" grow out of absolutely nothing on the Internet, and it gets me now and again. The time would've been far better and more effectively spent working on my design project so that I can actually build something someday, but I spent it this way instead. >sigh<

    In the spirit of moving on, does anyone know what those two little vents are just under the rear wing of the BlackFly? They may have been mentioned much earlier in the thread, but I can't find that part of the discussion and I'm curious. Or that cluster of antennas just behind the canopy? The latter is probably part of the ability to control it remotely, if desired?

    Hmm. I don't see that. The bottom of the "fuselage" is a pretty narrow skid, if I'm getting a good view of it. With the fuselage/hull in the resting-on-ground position, the props are at about a 45° nose-up angle. Even with the "blowing" effect, that's asking a lot, and most of the lift is still going to come from the props. Scooting forward on the ground or in the water, with the hull in the at-rest orientation, is probably going to nose-down the front props dangerously close to the ground/water, since the drag of the fuselage/hull bottom is well below the vertical location of the CG, which shows when the thing pitches over into cruise. If this operation were practical, I would think you'd see them doing nearly level powered-lift takeoffs and immediate transitions to a climb-out and cruise in order to conserve power. Possible it was promotional, but all their takeoffs and landings were vertical or very nearly so, with the nose well up above the horizon.

    I think you might get a little bit of a "skidding" takeoff if you tried to take off level, but the wings would still be contributing almost nothing to the lift, and the props would still be doing the big majority of the work.
     
    Last edited: Aug 3, 2018
  4. Aug 3, 2018 #464

    pictsidhe

    pictsidhe

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    Here's a boxkite wrapped around a quadcopter. Note that the QC is well forward. Presumably to give some static margin. This sort of rig would be ideal for exploring how well an OTS drone controller can handle a -ve margin wing-drone.

    [video]https://m.youtube.com/watch?v=pdExM7pwCAs[/video]

    C'mon, I only need the flimsiest of reasons to post this!
     
  5. Aug 3, 2018 #465

    mcrae0104

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    I couldn't tell what function they were performing. They're really pretty small.
     
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  6. Aug 3, 2018 #466

    Topaz

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    From the orientation and their shape, I'd guess they're exhausting something. Cooling air for the computers, perhaps?
     
  7. Aug 3, 2018 #467

    mcrae0104

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    Yep, might be as pedestrian as a cockpit exhaust vent. I didn't ask. Speculation is fun, ain't it? :)
     
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  8. Aug 3, 2018 #468

    henryk

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    -the central part of BF fuselage with pilot can be ejected via BRS !
    -the second BRS for lowering landing speed of "non human" part...
     
  9. Aug 3, 2018 #469

    henryk

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  10. Aug 3, 2018 #470

    markaeric

    markaeric

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    Some observations:

    From watching the videos, the elevons are used in all phases of flight. This gives me the impression that the outboard motors are more critical than the inboard ones.

    As henryk just pointed out, there is a "classic" takeoff mode. In reality, it probably lifts slightly off the surface first (but shouldn't have to other than to protect the belly), and the blown airfoils provide significant lift at near zero forward velocity when they're basically parallel to the horizon. This is some seriously impressive STOL performance. This is probably the coolest demonstrations I've ever seen of an aircraft with blown wings.


    I think, but I haven't seen anything conclusive, the front and rear wing angles aren't parallel. What purpose would that serve? Perhaps an efficient way to trim out horizontal flight?

    That large array of antennas on top of the fuselage are most likely for remote control. I forgot where I read that the majority of their testing was done remotely.


    BBerson: since you tried out the simulator, could you elaborate on the joystick controls? How did it operate?


    The FBW software is most definitely more sophisticated than some of you are giving it credit for. A regular multirotor is pretty straight forward, this is quite a bit more complex - there's at least two distinct flight modes, with one of them being particularly unusual. Also consider the fact that while the motors are operational, the airfoils are generating lift perpendicular to the wings.

    Implementing a redundant FBW system really is pretty challenging. Having redundant computers is straight forward enough, but propagating those redundant signals to their endpoint is a lot less so. There's a handful of different methodologies, and they're more involved than "Step 1: Collect underpants. Step 2: ________. Step 3: Profit!"


    And yes, Opener and Black Fly are both awful names. Also, their promo videos and the fact that they didn't fly at Osh rubbed me the wrong way. And just maybe everyone that works for the company is an a-hole and they're somehow taking advantage of and plotting the death of part 103. But as far as the aircraft is concerned, it really is a radical and clever design and that's something I think all of us here should be able to appreciate.
     
  11. Aug 3, 2018 #471

    henryk

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    Last edited: Aug 3, 2018
  12. Aug 3, 2018 #472

    Aesquire

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    The "tail sitter" VTOL aircraft designs, French, American, German, etc. actually flown, or not, have all suffered from serious flaws in the real world, which is why you don't see them filling the decks of mini aircraft carriers. See Carrier comment below.

    One bad thing about tail sitters (TS, for this post ) is that conventional airplanes aren't good going backwards. Like throwing an arrow backwards, the aerodynamics make the tail "want" to be behind. You don't back down at any appreciable speed. Or you flip over. Result? S!ow, fuel wasteful, landing ops.

    Falcon boosters have tail fins and land nose first. It's just that flying to landing mode is opposite to take off ballistic mode. Or.... It takes off, tail first. With tail folded. Feel free to argue semantics.

    Another problem with TS designs is pilot visibility for landing. Poor view of the ground, over the pilot's shoulder, in a Jack knife seat position, or that never flown, German WW2, Heinkel Lerch, prone position, also a bit awkward.....

    BlackF!y simply ignores the problems. Seeing the ground beneath you isn't an option. In hover you are head down, on your back, looking more or less backwards & up. The designers said "who cares? Push the Land button".

    And when coming in to land, it transitions to a multi copter drone mode with artificial stability, thus solving the instability going backwards problem..... By brute force and computer subtlety.

    Thank you for confirming my W A Guess that Black Fly has differently angled ( incidence ) wings, thus providing tandem wing/staggered biplane pitch stability in cruise flight. My paper airplane ( glider ) models work if the incidence is correct. Fairly broad CG range, too. Much like a Pou, or a reversed Easy Riser. This would substantially reduce power consumption in cruise by reducing the need for stability augmentation.


    Aircraft Carrier Note. Skip it you like, a bit off topic, but perhaps not as much as arguing BRS stall speed.

    Since WW2, VTOL aircraft, specifically fighter/bombers ( almost all modern fighters can also drop bombs ) have been desired by Air Forces, because the first target in a War is the air fields. Modern jets, heck, any heavy airplane, generally don't like muddy, grass covered open fields. That requires heavier, tougher, landing gear. B-17s were designed for open grass fields. B-29s were designed for hard surface runways..... Rare at the beginning of WW2, and of a length unheard of in 1939. The Swedes designed fighters to land on highways, and provided refueling/re-arming stations on their highways to match. Other Western Air Forces invested in rocket launched or VTOL designs, then gave up and now pretend they can operate on day 2 of a real war. Denial isn't just a river in Egypt.

    The U.S. Navy should be acutely aware that Super Carriers are expensive, we don't have "enough" of them ( A major argument in funding and defense I shall not address here ) and the reason there aren't enough of them is the enormous loss in capability one sinking is, as a percentage of total capability. Some have long advocated less capable, but more numerous, carriers, like the Jeep carriers of WW2. But we don't have aircraft that work on a Guadalcanal sized boat. Except Harriers. ( the only successful VTOL military aircraft without rotors ) The Navy would love many, small, VTOL, carriers, if there were airplanes that could do the job with the range they desire, and they had the budget. It would be a paradigm shift. Alas, the planes don't exist.

    End rant.
     
  13. Aug 3, 2018 #473

    BJC

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    No.


    BJC
     
  14. Aug 3, 2018 #474

    Hot Wings

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    For vertical mode that would probably be sufficient. How does the software decide that the 'pilot' wants to transition to forward mode and not just move around laterally in the vertical mode? At what point does the software transition from vertical mode, using prop thrust and torque for maneuvering, to horizontal mode where the ailerons operate in a different axis relative to the earth?

    As forward airspeed increases, the motors would find themselves running under reduced power.
    During transition the load would actually increase until the forward speed increased the mass flow to the prop or the wings started to carry lift. The power required during the initial stages of transition will be greater.

    static margin is negative as it would be if the cg is midway between the wings

    Static margin is pretty much irrelevant - strike that - it is irrelevant, it's FBW so the static margin can actually be negative. But it would only come into play if all propulsive power were lost.

    The usual voting on multiple controllers is a simple majority

    Depends on how the data was gathered. Much like human democracies the majority can be wrong. With multiple data points that have been averaged and cross checked for reasonableness a simple comparison vote might work well enough?
    The X-29 software had a potential problem of this sort but it was deemed acceptable because they had humans watching the data in real time and there was a back up system in place.

    I've seen one video that shows it taking off on grass with a forward 'roll' of only about 2 lengths with a moderate rotation. It's linked somewhere in the above 400ish posts :whistle:

    I hadn't noticed that - will have to look closer. In vertical mode in order to remain stationary over a point the 'ailerons' will either need to be fully reflexed or the craft actually slightly over on it's back so that the sum of the lift vectors from the wings and props are vertical. Edit: just noticed you understand this too.
     
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  15. Aug 3, 2018 #475

    Aesquire

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    :roll:
     
  16. Aug 3, 2018 #476

    BBerson

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    "BBerson: since you tried out the simulator, could you elaborate on the joystick controls? How did it operate?"

    I wasn't going to respond to individuals on this thread because almost every observation I had gets twisted...

    It had a typical joystick for pitch and roll that was normal. It had sort of a coulee hat button on top of the stick that controlled throttle/altitude. Normally that would be pitch trim, so my helicopter experience prevented me from operating it correctly in the 60 seconds of sim time I had. (long line of kids waiting).
    Hence my "designed by industry outsiders" comment.
     
  17. Aug 3, 2018 #477

    Hot Wings

    Hot Wings

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    Useful info. Thanks!
    When you say pitch and roll were 'normal' does that mean that roll moved the craft with respect to it's longitudinal axis in both vertical and horizontal flight or was there the equivalent of a rudder via stick twist?
    The throttle/attitude: Was it incremental, like setting trim in a conventional aircraft, or did you have to use continuous input to maintain/accelerate?
     
  18. Aug 3, 2018 #478

    BBerson

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    If the stick had twist the instructor didn't tell me and I didn't notice. (I have twist on my sim at home). It seemed to bank and coordinate the turn with simple right stick only. No peddles.
    The up down toggle was for throttle/altitude/forward speed (disregard "attitude" typo above).
    Kind of like a R/C drone but they have two control sticks.
    So it wasn't like a helicopter with collective, nor was it like any R/C drone.
    If it had two sticks like my drone I would have made a perfect landing. Anything can be learned with more time.
     
    Last edited: Aug 3, 2018
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  19. Aug 3, 2018 #479

    davidb

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    I’m having trouble visualizing how one coordinates altitude with forward speed if its the same switch. I guess one has to move the stick fore and aft at the same time? I’ve never flown a drone so forgive my ignorance.
     
  20. Aug 3, 2018 #480

    Hot Wings

    Hot Wings

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    That is the basics of my question as well. Typical Drone 2 stick:
    How-to-Fly-a-Quadcopter-Transmitter-Image.jpg

    The up down/throttle is an active control, not a trim setting for constant speed or altitude hold, though such is available via software. So specific questions:

    During transition from vertical hover to forward flight does the 'pilot' need to increase the power to maintain a constant altitude or do they simply push the stick forward and let the software adjust power as needed?

    During forward flight does a forward stick command result in increased speed or does the software reduce the power for a decent at the previously chosen speed?
     

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